Building the Walford Electronics Ivel Receiver.
Richard White G6NFE enjoys building the Ivel receiver from Walford Electronics.
Richard White G6NFE enjoys building the Ivel receiver from Walford Electronics.
Ihadn’t built anything in kit form for about 38 years, but after a long lapse in amateur radio and renewing my licence in 2015 after discovering I could now use the HF bands with my 1982 ‘Class B’ licence, it was time to try my hand at building and testing again. At the back of my mind was the memory of the embarrassing letter I received in the post 38 years ago after complaining to the manufacturer that their kit ‘didn’t work’, only to have my poor construction skills pulled apart and my glaring errors highlighted and corrected (for a small fee)!
Could I build a modern radio in kit form? Did I have the requisite soldering skills? Could I remember the resistor colour codes? As it turned out I needn’t have worried, the instructions with the Walford Electronics kits are excellent as I will explain later.
An Idea Comes to Fruition
The idea to try kit building again had probably been forming in my mind for some time. In 2019 I purchased some used RF test equipment, checked it, and satisfied it all worked, neatly stacked it away determined to find a use for it. Originally, I intended to refurbish some old Yaesu hybrid HF transceivers, but in a small house with four family members and a lively Greyhound, finding the space to tear them apart proved impossible.
Then came the chaos and fallout from Covid-19. No more shopping, cinema, coffee shops, restaurants, socialising, etc. What to do? How much TV can you consume before enough is enough? How many times have you tried a new author only to find the new book isn’t doing it for you? Hmmm. I needed to find something I could dive into, think carefully about what I was doing and start remembering things long forgotten.
Most importantly, I had to be able to walk away from it when I wanted and then pick it up where I left off. Then the penny dropped. I had vague recollections of an article about the Halse and Hatch HF radio kits from Walford Electronics.
Finding the Walford Electronics website completely convinced me. After drooling through the various pages, I somehow and rather foolishly, convinced myself I could build the most complex kits and I would have them working perfectly in shiny enclosures beautifully hand crafted by myself. The power of dreams. Oh dear.
The Kit Arrives
The Halse and Hatch duly arrived along with the frequency counter kit and the power amplifier kit. Inside was a polite note from Tim Walford advising me to take it slow. Hmmm. Does he know something I don’t? The answer is undoubtedly yes, he does. I think what he was trying to tell me was “take it easy, these kits require real care, preparation, consideration, manual dexterity, test equipment and lots of patience”. Not to mention the use of skills that in my case I hadn’t practiced for many years, such as soldering and desoldering….
The reality hit me like a brick. I’d taken on too much, too soon. My ambitions and imagination were writing cheques my kit building abilities couldn’t cash. Without admitting my over ambition to my wife, I quietly put the kit parts to one side and had a re-think. About a month passed and then one day I just happened to be on the Walford Electronics site again. I’d found the answer. I would start out with something simpler, much simpler. And so, the logic went as follows: I ordered the Ivel HF receiver classified as a ‘simple’ kit, and also the Ilton HF transmitter, classified as an ‘intermediate’ kit. If, and it was a big if, I could get these working then, and only then, would I attempt the Halse and Hatch with the frequency counter and power amplifier.
Credit Card Time
Out came the credit card again. Here goes. Better get it right this time! As before, the Ivel and Ilton arrived in good time and very well packaged. Tim is very good at letting you know how things are progressing with the order as well as replying to any technical questions that may arise.
After obtaining the required authorisation from my wife I reserved an area of kitchen worktop with a promise it would all be cleared away well before dinner in the evening. Woe betide the
amateur radio kit builder who holds up dinner and leaves a mess on the kitchen worktop!
Thinking about what I needed I reasoned on: (a) biscuit tin with lid, (b) soldering iron, (c) DMM, (d) some basic tools such as cutters, pliers, tweezers, and also (e) a power supply of some description. The frequency counter and signal generator could wait until further down track; I didn’t need them now.
Getting Started
Each kit comes in its own clear plastic bag with very clear instructions and colour photographs to help you understand the layout of the board. At this stage I recommend the builder puts the kits still inside their bags into a biscuit tin with a tight-fitting lid. This will reduce the chances of the accidental escape and potential loss of extremely small parts.
On examining the Ivel it is immediately apparent just how much thought has gone into developing the radio. The components appeared to be of the best quality and the instructions are clear once read and reread a number of times.
This is also a good time to print off a resistor colour code chart if like me, you last looked at these 38 years ago! That said, the instructions do give you the colour codes and also explain what numbers to look for on other components such as capacitors, ICs and so on.
The instructions recommend building and testing the Ivel in stages and this is what I did. To minimise any build issues, I ticked each individual component off as I populated the board. The instructions recommend the soldering of the front panel to the main PCB before adding the pots and switches, but I wasn’t sure I wanted to do this because of my lofty (read expensive) ambitions to mount the whole project in a metal enclosure.
So, after some thought, I applied a few dabs of super glue and prayed it would work. It did. Enough to hold it together, but not so much I’d damage the board when disassembling it later. A word of caution here: The instructions do not recommend this procedure. It was a personal choice. You have been warned!
Mechanical assembly was easy with all the parts fitting without issues and the colour photos were really useful as a
reference. The value of the photographs becomes even more apparent as the build progresses.
Next came the electrical assembly. This started off easily enough; certainly, the two screw connector blocks, the stereo jack and the metal canned inductors are easy to locate and fit.
Moving to the smaller components raised the first challenge. My 58 year-old eyes are not quite as sharp as they used to be. I installed a resistor only to realise later that I had managed to confuse red with orange. Lessons learned; make sure you have very good lighting and, if required, a small magnifying glass to hand. One thing I did discover was the true ‘Swiss Army Knife’ ability of the modern smartphone. Using the camera with the built-in LED flash switched on, I magnified the image on the screen.
The results were outstanding and the impossible to read digits on the tiny Polyester capacitors were crystal clear. Oh, one other thing, use a good quality DMM if you have any doubts about the value of the resistor you are about to fit.
I carefully worked my way to the end of stage 1 and connected the wires on the ‘fine’ pot to the main board as described. The power supply was connected with the lowest power output I could select and the time had come. Power was applied. No smoke, no supply trip, no horrible smells. Measuring the voltage on point 8 showed 7.94 volts. Near enough to 8 volts. Phew!
Working through the Build
Working through the subsequent stages was not difficult. All you have to do is follow the instructions step-by-step and if text is in bold print there is a good reason for it! I made a note of all test voltage readings I got and ticked each stage off line by line. The only voltage that caused me concern was at the end of stage 4 where I measured 5.62 volts. A quick e-mail to Tim Walford confirmed it was near enough to the 6 volts required. Result.
Stage 6 is the stage you need to be decisive about. Choose your band and stick to it as the specific band is defined by the inductors and capacitors you choose at this stage. Something to point out here is the 20 metre band. As supplied, the kit covers the 30, 40 and 80 metre bands. If you want to use 20 metres, you need to flag this up when you order the kit. I chose the 40 metre band.
This final stage is where all the concentration and diligence comes together. Applying power, antenna and headphones, I could hear RTTY and CW. Obviously, it needed final alignment but it worked. Yes! The embarrassment of 1982 melted away. I could build a kit and, more importantly, it worked as the designer intended.
Testing, Testing
After this I decided it was time to break out the 2019 designer collection of RF test equipment. Hooking up my budget (extremely cheap) Chinese frequency counter to a divide-by-10 probe and a 150pF capacitor in series was not successful. The frequency wandered from 2.8MHz to 8MHz. Clearly it wasn’t up to the job and demonstrated the value of good quality test equipment.
Thinking about it later it’s entirely possible the counter was not at fault as I didn’t install any vero pins in the test points on the main board. I recommend you do this because it could save a lot of frustration.
Lastly, I hooked up my signal generator to the antenna port on the board and extremely cautiously applied a test signal of −120dBm at 2kHz and 70% modulation on 7.150MHz AM. Astute readers will now realise why I couldn’t hear the test signal on the Ivel receiver. Another quick e-mail to Tim Walford and he pointed out the error of my thinking. How on earth did I expect to hear a test signal at −120dBm? As he said, S9 is considered to be −75dBm. I would have to come up a very long way….
Moving swiftly on from this ‘schoolboy error’ I could hear the test signal clearly. I aligned the receiver to be centred around 7.150MHz and this worked for me as I prefer the SSB segment of the band. Finally, I peaked up L2 and L3 for maximum signal strength and that was it. Job done.
Conclusion:
The Ivel is a good place to start if, like me, you haven’t touched a kit or seriously played with components for a long time. The instructions are completely logical and very clear. It is entirely possible to build and test it with only a digital multimeter and another HF receiver to monitor the Ivel’s VFO. You certainly don’t need a frequency counter or signal generator. As I said earlier, the value of the colour photos becomes more evident as you move through the build, allowing you to sanity check the placement of components before you solder them in place. Technical support from Tim Walford is available if required, but to be honest the instructions are good enough that you rarely need it. A good quality receiver and highly recommended.